US20030122807A1 - Display unit, information processing unit, display method, program, and recording medium - Google Patents
Display unit, information processing unit, display method, program, and recording medium Download PDFInfo
- Publication number
- US20030122807A1 US20030122807A1 US10/248,149 US24814902A US2003122807A1 US 20030122807 A1 US20030122807 A1 US 20030122807A1 US 24814902 A US24814902 A US 24814902A US 2003122807 A1 US2003122807 A1 US 2003122807A1
- Authority
- US
- United States
- Prior art keywords
- mode
- display unit
- display
- pixels
- panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3685—Details of drivers for data electrodes
- G09G3/3688—Details of drivers for data electrodes suitable for active matrices only
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2092—Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0202—Addressing of scan or signal lines
- G09G2310/0213—Addressing of scan or signal lines controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0264—Details of driving circuits
- G09G2310/0275—Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/04—Maintaining the quality of display appearance
- G09G2320/043—Preventing or counteracting the effects of ageing
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/08—Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
- G09G2330/02—Details of power systems and of start or stop of display operation
- G09G2330/021—Power management, e.g. power saving
- G09G2330/023—Power management, e.g. power saving using energy recovery or conservation
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2011—Display of intermediate tones by amplitude modulation
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3614—Control of polarity reversal in general
Definitions
- the present invention relates to a display unit, information processing unit, display method, and recording medium. More particularly, it relates to display unit or information processing unit equipped with a panel in which pixels are arranged in a matrix as well as to a related display method, program, or recording medium.
- Japanese Published Unexamined Patent Application No. 10-31464 discloses a technology for reducing voltage fluctuations in output signals of scan line drivers feeding voltage to row direction pixels and data drivers feeding voltage to column direction pixels in an in-plane switching (IPS) liquid crystal display by providing two values--low and high--of potential to be applies to common lines feeding to all pixels and by reversing them on a frame by frame basis.
- IPS in-plane switching
- Japanese Published Unexamined Patent Application No. 9-33888 discloses a liquid crystal display, which comprises a first drive mode for applying a selection voltage to each common electrode which feeds voltage to row direction pixels; a second drive mode for applying a selection voltage to each common electrode group organized along the column direction, wherein the second drive mode reduces power consumption.
- Japanese Published Unexamined Patent Application No. 5-323902 discloses a liquid crystal display which comprises a circuit for converting data by controlling external signals based on a predetermined law, in a data line drive circuit for supplying voltage to row direction pixels, and achieves long life by creating a display using converted display data.
- Japanese Published Unexamined Patent Application No. 10-124006 discloses a portable information terminal which automatically adjusts liquid crystal drive voltage in accordance with a bias ratio to achieve an optimum contrast ratio when the user adjusts the bias ratio of a liquid crystal display.
- a display unit which visually displays information for the user, should allow the user to make appropriate trade-offs between easy screen viewing and low power consumption even in low-power mode such as power saving mode or life extension mode.
- a purpose of the present invention is to provide a display unit, information processing unit, display method, program, and recording medium which can solve the above problem. This purpose is served by a combination of features set forth in the independent claims herein.
- the dependent claims further present advantageous concrete examples of the present invention.
- a first aspect of the present invention provides a display unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting a display mode of the above described display unit to one of a plurality of the above described display modes; a voltage supply section for changing a drive voltage which serves as a reference voltage for voltage supplied to the above described panel, according to the above described display mode set by the above described mode setting section; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage.
- the above described display unit may be a normally black display unit in which the luminance of the above described pixel decreases with decreases in a potential difference applied to the above described pixel by the above described pixel drive voltage.
- a second aspect of the present invention provides a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, including: a data receiver for receiving an image frame which corresponds to one screen of image data from outside at preset intervals; a drive for setting luminance for each of the above described plurality of pixels in the above described panel and displaying the above described image on the above described panel; and a mode setting section for setting the above described display unit to one of display modes, including a normal mode which makes the above described display unit create a normal display and a restricted mode, wherein in the above described restricted mode, the above described drive sets an available range of the above described luminance for one part of the above described pixels used to display the above described image frame such that it will be different from an available range of the above described luminance for another part of the above described pixels used to display the above described image frame.
- a third aspect of the present invention provides a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, including: a drive for supplying each of the above described plurality of pixels in the above described panel with a voltage for setting luminance for the pixel; and a mode setting section for setting the above described display unit to one of display modes, including a normal mode which makes the above described display unit create a normal display and a restricted mode, wherein the above described drive periodically reverses polarity of a potential difference applied to the above described pixel by the above described pixel drive voltage, and the above described drive sets the cycle of polarity reversal of the above described potential difference applied to the above described pixel in the above described restricted mode such that it will be longer than that in the above described normal mode.
- a fourth aspect of the present invention provides a display unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting a display mode of the above described display unit to one of a plurality of the above described display modes; a current supply section for changing a drive current which serves as a reference current for current supplied to the above described panel, according to the above described display mode set by the above described mode setting section; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive current generated according to luminance data which specifies luminance of the given pixel and to the above described drive current.
- a fifth aspect of the present invention provides an information processing unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting the above described panel to one of display modes, including a normal mode which makes the above described panel create a normal display and a restricted mode which restricts a luminance range of the above described pixels in comparison to the above described normal mode; an instruction section for making the above described panel set the above described display mode to the above described restricted mode upon fulfillment of the necessary condition that there is no user input for a certain period of time; a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel and restricting a luminance range of the above described pixels in comparison to the above described normal mode when the above described restricted mode is entered; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with
- a sixth aspect of the present invention provides an information processing unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting the above described panel to one of display modes, including a normal mode which makes the above described panel create a normal display and a restricted mode which restricts a luminance range of the above described pixels in comparison to the above described normal mode; an instruction section for making the above described panel set the above described display mode to the above described restricted mode upon fulfillment of the necessary condition that the frequency at which the above described image memory is updated is lower than a preset value; a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel and restricting a luminance range of the above described pixels in comparison to the above described normal mode when the above described restricted mode is entered; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based
- a seventh aspect of the present invention provides a display method for controlling a display unit equipped with a panel in which pixels are arranged in a matrix, a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel, a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel, and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage, the above described display method including the steps of: setting the above described display unit to one of a plurality of display modes; and changing the above described drive voltage according to the above described display mode selected.
- an eighth aspect of the present invention provides a program for an information processing unit, the above described program controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein: the above described information processing unit outputs luminance data of a plurality of the above described pixels which form images to the above described display unit and thereby displays the above described images on the above described display unit; and the above described program comprises a mode setting module for making the above described information processing unit set the above described display mode of the above described display unit to either a normal mode in which the above described display unit creates a normal display or a low-power mode which reduces power consumption of the above described display unit compared to the above described normal mode, and set frequency at which the above described information processing unit outputs the above described luminance data in the above described low-power mode such that it will be lower than that in the above described normal mode.
- a ninth aspect of the present invention provides a storage medium containing a program for an information processing unit, the above described program controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein: the above described information processing unit outputs luminance data of a plurality of the above described pixels which form images to the above described display unit and thereby displays the above described images on the above described display unit; and the above described program comprises a mode setting module for making the above described information processing unit set the above described display mode of the above described display unit to either a normal mode in which the above described display unit creates a normal display or a low-power mode which reduces power consumption of the above described display unit compared to the above described normal mode, and set frequency at which the above described information processing unit outputs the above described luminance data in the above described low-power mode such that it will be lower than that in the above described normal mode.
- a tenth aspect of the present invention provides a program for controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein the above described display unit includes: a mode setting module for making the above described display unit set itself to one of display modes, including a normal mode in which the above described display unit creates a normal display and a restricted mode; and an image conversion module for making the above described display unit convert, in the above described restricted mode, an available range of the above described luminance for one part of the above described pixels used to form an image displayed on the above described display unit, such that it will be different from an available range of the above described luminance for another part of the above described pixels used to form the above described image.
- an eleventh aspect of the present invention provides a storage medium containing a program for controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein the above described program includes on the above described display unit: a mode setting module for making the above described display unit set itself to one of display modes, including a normal mode in which the above described display unit creates a normal display and a restricted mode; and an image conversion module for making the above described display unit convert, in the above described restricted mode, an available range of the above described luminance for one part of the above described pixels used to form an image displayed on the above described display unit, such that it will be different from an available range of the above described luminance for another part of the above described pixels used to form the above described image.
- a mode setting module for making the above described display unit set itself to one of display modes, including a normal mode in which the above described display unit creates a normal display and a restricted mode
- an image conversion module for making the above described display unit convert, in the above described restricted mode, an
- Figure 1 is a diagram showing a configuration of an information processing unit 100 according to an embodiment of the present invention.
- Figure 2 is a diagram showing a configuration of an output device 150 according to the embodiment of the present invention.
- Figure 3 is a diagram showing a configuration of a panel 230 according to the embodiment of the present invention.
- Figure 4 is a diagram showing a configuration of a source driver 270 according to the embodiment of the present invention.
- Figure 5 is a graph of relationship between potential differences applied to pixels 310 and luminance of the pixels 310 according to the embodiment of the present invention.
- Figure 6 is a diagram showing display modes set by a mode setting part 240 in a tabular form, according to the embodiment of the present invention.
- Figure 7 is a graph showing potential differences applied to the pixels 310 in each display mode according to the embodiment of the present invention.
- Figure 8 is a diagram showing a process flow of a display control program 180 running on the information processing unit 100 according to the embodiment of the present invention.
- Figure 9 is a diagram showing a configuration of a display unit 200 according to a variation of the embodiment of the present invention.
- Figure 1 shows a configuration of an information processing unit 100 according to this embodiment.
- the information processing unit according to this embodiment 100 comprises a CPU 110, ROM 115, RAM 120, communications interface 125, hard disk drive 130, floppy disk drive 135, CD-ROM drive 140, input device 145, output device 150, system control circuit 155, and input/output bus 160.
- the CPU 110 operates based on programs stored on the ROM 115 and RAM 120 and controls various components.
- the communications interface 125 communicates with other devices via a network.
- the hard disk drive 130 stores programs and data used by the information processing unit 100 and supplies programs to the RAM 120 based on instructions from the user of the information processing unit 100.
- the floppy disk drive 135 reads programs or data from a floppy disk 165 and supplies them to the RAM 120.
- the CD-ROM drive 140 reads programs or data from a CD-ROM 170 and supplies them to the RAM 120.
- the input device 145 allows the user of the information processing unit 100 to enter instructions.
- the output device 150 displays images, including characters and/or graphics, for the user, based on instructions from programs operating on the information processing unit 100.
- the system control circuit 155 connects the CPU 110, ROM 115, RAM 120, communications interface 125, hard disk drive 130, floppy disk drive 135, CD-ROM drive 140, input device 145, and output device 150 with each other.
- the input/output bus 160 connects the system control circuit 155 with the communications interface 125, hard disk drive 130, floppy disk drive 135, CD-ROM drive 140, input device 145, and output device 150.
- the hard disk drive 130 stores a display control program 180 which runs on the CPU 110.
- the display control program 180 is started by the user or by the operating system which runs on the information processing unit 100. It controls the output device 150.
- the display control program 180 includes a mode setting module 185, instruction module 190, and image conversion module 195. These modules are programs which make the information processing unit 100 operate as a mode setting section, instruction section, and image conversion section on the information processing unit 100.
- the mode setting module 185 sets display mode of a display unit in the output device 150 to either a normal mode for normal display or a low-power mode intended to reduce power consumption and extend the life of the display unit.
- the low-power mode is an example of reduced mode according to the present invention.
- the instruction module 190 instructs the mode setting module 185 to set the display mode to the low-power mode upon fulfillment of preset conditions.
- the instruction module 190 may, for example, monitor the input device 145 and make the output device 150 go into the low-power mode upon fulfillment of the necessary condition that there is no user input for a certain period of time.
- the image conversion module 195 converts, as required, images displayed by the display unit in the output device 150 so that the display unit in the output device 150 can operate at lower power.
- the display control program 180 is supplied by the user, being stored on a recording medium such as the floppy disk 165 or CD-ROM 170.
- the display control program 180 is read from the recording medium, installed in the information processing unit 100 via the floppy disk drive 135 or CD-ROM drive 140, and executed on the information processing unit 100.
- the programs or modules described above may be stored on an external storage medium.
- various storage media are available including optical recording media such as a DVD and PD, magneto-optical recording media such as an MO, tape media, and semiconductor memories such as an IC card.
- the programs may be supplied to the information processing unit 100 via a dedicated communications network or the Internet using a hard disk, RAM, or other storage device which serves as a recording medium having been installed in a server system connected to the network.
- Figure 2 shows a configuration of the output device 150 according to this embodiment.
- the output device 150 according to this embodiment comprises a display unit 200, control circuit 210, and image memory 220.
- the display unit 200 displays images, including characters and/or graphics, for the user, based on instructions from programs operating on the information processing unit 100.
- the control circuit 210 controls the display unit 200 as well as the image memory 220 which stores luminance data of each pixel in image data, and thereby carries out an image data storage process, image data output process, and display mode setting process.
- the control circuit 210 receives data which composes images from the CPU 110 via the system control circuit 155 and stores it in the image memory 220 as image data which includes the luminance of each pixel on screen.
- the control circuit 210 may calculate the luminance of each pixel based on information about objects such as rectangles and points which compose the images by receiving it from the CPU 110.
- the control circuit 210 may directly receive addresses on the image memory 220 and write data from the CPU 110 and store the write data at the appropriate addresses in the image memory 220.
- the control circuit 210 reads the luminance data of each pixel in the image data from the image memory 220 and transmits it in sequence to the display unit 200.
- the control circuit 210 outputs a data transfer clock to the display unit 200 in synchronization with a data signal for outputting the luminance data of each pixel to the display unit 200.
- the control circuit 210 sets the display mode of the display unit 200 to either the normal mode or low-power mode based on the setting of the mode setting module 185 which runs on the CPU 110.
- the control circuit 210 at least outputs a screen-saving signal instructing the display unit 200 to enter the low-power mode or prolongs the cycle of image data output to the display unit 200.
- the control circuit 210 lengthens the time required to transmit the luminance data of each pixel to the display unit 200 and lowers the frequency of the data transfer clock.
- the display unit 200 comprises a panel 230, signal receiver 235, data receiver 285, clock receiver 280, timing controller 290, mode setting section 240, voltage supply section 250, and drive 255.
- the panel 230 has pixels arranged in a matrix.
- the panel 230 according to this embodiment is a liquid crystal panel on which the luminance of pixels is set according to potential differences applied to them. It is a normally black type on which pixels are displayed in black when no potential difference is applied to them.
- the panel 230 may be a liquid crystal panel which employs AFLC technology, MIM elements, TFT-based OCB mode, IPS mode, or MVA mode.
- the panel 230 may be a display panel other than a liquid crystal panel which sets the luminance of pixels according to potential differences applied to them.
- the panel 230 may be a normally white type in which pixels are displayed in white when no potential difference is applied to them.
- the signal receiver 235 receives a screen-saving signal outputted by the output device 150 in the control circuit 210 upon fulfillment of the necessary condition that there is no user input for a certain period of time.
- the data receiver 285 receives the luminance data of each pixel in the image data as a data signal from the control circuit 210.
- the clock receiver 280 receives the data transfer clock inputted in synchronization with the data signal for inputting the luminance data. Based on the data transfer clock received by the clock receiver 280, the timing controller 290 outputs, to the gate driver 260 and source driver 270, timing signals for driving them. Also, the timing controller 290 outputs the luminance data to the source driver 270 in synchronization with the timing signals.
- the mode setting section 240 sets the display mode of the display unit 200 to the low-power mode if the signal receiver 235 receives a screen-saving signal and/or if the clock receiver 280 receives a data transfer clock with a lower frequency than that in the normal mode. On the other hand, if the conditions setting for the low-power mode are not satisfied, the mode setting section 240 sets the display mode of the display unit 200 to the normal mode.
- the mode setting section 240 sets six display modes for the display unit 200: Modes 1 to 6.
- Mode 1 is a display mode which makes the display unit 200 create a normal display.
- Modes 2 to 6 are display modes which make the display unit 200 create a low-power display.
- Mode 2 is a low drive voltage display mode.
- the mode setting section 240 makes the voltage supply section 250 supply the source driver 270 with a drive voltage which restricts the luminance range of pixels on the panel 230 in comparison to the normal mode.
- the mode setting section 240 selects one of the five low-power display mode based on a setting specified by the user of the information processing unit 100 and/or an instruction from the display control program.
- the voltage supply section 250 supplies voltage used to operate the drive 255. Also, the voltage supply section 250 changes a reference voltage for the voltage supplied to the panel 230 by the source driver 270 in the drive 255, in accordance with the display mode set by the mode setting section 240.
- the drive 255 drives the panel 230 based on image data to display the image data on the panel 230.
- the drive 255 includes the gate driver 260 and source driver 270.
- the gate driver 260 supplies a selection signal to a plurality of pixels arranged in the row direction on the panel 230.
- the source driver 270 supplies each of the pixels selected based on the selection signal from the gate driver 260 with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the drive voltage from the voltage supply section 250.
- Figure 3 shows a configuration of the panel 230 according to this embodiment.
- pixels each of which contains a pixel 310 and corresponding switching element 300 are arranged in the row and column directions.
- the pixel 310 sets its luminance based on the potential difference between the pixel drive voltage VDx and a common voltage Vcom.
- the pixel 310 functions also as a capacitor which retains the supplied pixel drive voltage VDx.
- the gate driver 260 and source driver 270 display an image frame constituted by one page of image data on the panel 230 as follows. First, the source driver 270 receives one row of luminance data from the control circuit 210. Next, the gate driver 260 sets the selection signal VGy of the pixels arranged in the given row (y-th row) to High. This turns on the switching elements 300 of the pixels arranged in the y-th row. Then, the source driver 270 supplies the appropriate pixel drive voltage VDx (in the case of the x-th column) to each of the pixels selected by the selection signal. Consequently, the pixels 310 in the pixels arranged in the y-th row are supplied with the corresponding VD0 to VDn.
- VDx in the case of the x-th column
- the gate driver 260 sets the selection signal VGy of the pixels arranged in the y-th row to Low (L Level). This turns off the switching elements 300 of the pixels arranged in the y-th row. Consequently, the pixels arranged in the y-th row retain VD0 to VDn supplied to them.
- the above operations allow the gate driver 260 and source driver 270 to set the luminance of the pixels arranged in the y-th row.
- the gate driver 260 and source driver 270 set the luminance of the (y + 1)th pixel in a manner similar to the one described above. By performing this operation for all the rows on one screen, the display unit 200 can display one screen of image data.
- the panel 230 displays each pixel in eight gradations. Also, it is assumed that the luminance data received by the display unit 200 from the control circuit 210 via a data signal is one of integer values 0 to 7. Incidentally, the display unit 200 according to this embodiment may use less than or more than eight gradations for display on the panel 230.
- the rows and columns according to this embodiment may be independent of the up, down, left, and right directions of the image shown to the user.
- the information processing unit 100 may display images on the panel 230 in such a way that the vertical direction of the images coincide with the column direction of the panel 230 or in such a way that the horizontal direction of the images coincide with the column direction of the panel 230.
- Figure 4 shows a configuration of the source driver 270 according to this embodiment.
- the source driver 270 according to this embodiment comprises, a shift register 400, sampling memories 410a to 410c, holding memories 420a to 420c, an inverter circuit 423, an inverter circuit 426, a transformer circuit 430, a transformer circuit 440, and output circuits 450a to 450c.
- the shift register 400 receives a timing signal which includes a start signal and data transfer clock from the timing controller 290.
- the start signal specifies, using H Level, when to start sending out luminance data for one row of pixels to the source driver 270.
- the shift register 400 sends out a clock ck to the sampling memory 410a while receiving the luminance data for the 0-th row from the data signal, sends out a clock ck to the sampling memory 410b while receiving the luminance data for the 1st row from the data signal, ..., and sends out a clock ck to the sampling memory 410c while receiving the luminance data for the last row from the data signal.
- the sampling memories 410a to 410c Upon receiving the clock ck from the shift register 400, the sampling memories 410a to 410c store the luminance data contained in the data signal. Then, the sampling memories 410a to 410c output the stored luminance data to the corresponding holding memories 420a to 420c. In this way, upon receiving the luminance data for one row of pixels from the timing controller 290, the sampling memories 410a to 410c output the luminance data of the pixels at the respective locations.
- the holding memories 420a to 420c store the luminance data outputted by the corresponding sampling memories 410a to 410c when a line display signal received from the timing controller 290 becomes High level. Then, the holding memories 420a to 420c output the stored luminance data to the corresponding output circuits 450a to 450c.
- the timing controller 290 sets the line display signal to High. Consequently, when the source driver 270 receives the luminance data for one row of pixels, the holding memories 420a to 420c output the luminance data for one row of pixels in synchronization with the line display signal.
- the inverter circuit 423 To invert the polarity of voltage applied to each pixel in even-numbered rows in the panel 230, the inverter circuit 423 generates an alternating drive voltage VA' by alternately inverting a drive voltage VA with respect to Vcom. Similarly, to invert the polarity of a voltage applied to each pixel in odd-numbered rows in the panel 230, the inverter circuit 426 generates an alternating drive voltage VB' by alternately inverting a drive voltage VB with respect to Vcom. The inverter circuit 423 and inverter circuit 426 set the inversion cycles of VA and VB, respectively, by receiving them from the voltage supply section 250.
- the transformer circuit 430 generates pixel drive voltages VA0 to VA7 to be supplied to the panel 230, using the alternating drive voltage VA' received from the inverter circuit 423 as a reference voltage.
- VA0 to VA7 are pixel drive voltages which correspond to the luminance data values 0 to 7.
- the transformer circuit 440 generates pixel drive voltages VB0 to VB7 to be supplied to the panel 230, using the alternating drive voltage VB' received from the voltage supply section 250 as a reference voltage.
- the output circuits 450a to 450c select the pixel drive voltages VA0 to VA7 or pixel drive voltages VB0 to VB7 and supply them to VD0 to VDn.
- the output circuits such as 450a for the even-numbered rows select respective pixel drive voltages from VA0 to VA7.
- the output circuits such as 450b and 450c for the odd-numbered rows select pixel drive voltages from VB0 to VB7.
- Figure 5 shows a graph of the relationship between potential differences applied to the pixels 310 and luminance of the pixels 310 according to this embodiment.
- the horizontal axis represents the potential difference applied to the pixels 310 and the vertical axis represents the luminance of the pixels 310.
- the solid line in Figure 5 represents the relationship between potential difference and luminance for a normally black type in which pixels are displayed in black when no potential difference is applied to them.
- pixels are displayed in black when the potential differences applied to them are no higher than Vlow2 and they are displayed in white when the potential differences applied to them are no lower than Vhigh.
- the luminance of the pixels is reduced with decreases in the potential differences applied to the pixels by the pixel drive voltages.
- the voltage supply section 250 sets VA and VB to Vhigh.
- the source driver 270 outputs pixel drive voltages with a potential difference in the range of Vlow2 to Vhigh to the panel 230.
- the voltage supply section 250 sets VA and/or VB to Vlow1.
- the source driver 270 outputs pixel drive voltages with a potential difference in the range of Vlow2 to Vlow1 to the panel 230.
- the voltage supply section 250 can set the drive voltage(s) VA and/or VB in the low drive voltage display mode at a level lower than those for the maximum luminance of the pixels in the normal mode.
- the voltage supply section 250 can reduce the range of potential difference applied to the panel 230 and lower the voltage used to drive the panel 230, and thereby reduce the power consumption of the display unit 200 compared to the normal mode.
- FIG. 5 The broken line in Figure 5 represents the relationship between potential difference and luminance for a normally white type in which pixels are displayed in white when no potential difference is applied to them.
- pixels are displayed in black when the potential differences applied to them are VWhigh and they are displayed in white when the potential differences applied to them are VWlow2.
- the luminance of the pixels increases with decreases in the pixel drive voltages.
- the voltage supply section 250 sets VA and VB to VWlow2.
- the source driver 270 outputs pixel drive voltages with a potential difference in the range of VWhigh to VWlow2 to the panel 230.
- the voltage supply section 250 may set VA and/or VB to VWlow1.
- the source driver 270 outputs pixel drive voltages with a potential difference in the range of VWhigh to VWlow1 to the panel 230.
- the voltage supply section 250 can set the drive voltage(s) VA and/or VB in the low-power modes at a level lower than those for the maximum luminance of the pixels in the normal mode.
- the voltage supply section 250 can reduce the range of potential difference applied to the panel 230, and in conjunction, for example, with a method for prolonging the inversion cycle of the inverter circuit 423 and/or inverter circuit 426, it can reduce the power consumption of the display unit 200 compared to the normal mode.
- Figure 6 shows the display modes set by the mode setting section 240 according to this embodiment in a tabular form.
- the mode setting section 240 according to this embodiment has the six display modes--Mode 1 to Mode 6--shown in Figure 6.
- Mode 1 is the normal mode while Mode 2 to Mode 6 are low-power modes different from each other.
- Figure 6 shows, for each of Mode 1 to Mode 6, transitions of the alternating drive voltages VA' and VB' outputted by the inverter circuit 423 and inverter circuit 426 during each cycle in which the display unit 200 displays one screen.
- the voltage supply section 250 supplies Vhigh to the drive voltages VA and VB.
- the inverter circuit 423 and inverter circuit 426 sets both VA' and VB' alternately to Vhigh and -Vhigh each time one screen is displayed.
- the voltage supply section 250 sets Vlow1 to the drive voltages VA and VB.
- the inverter circuit 423 and inverter circuit 426 set both VA' and VB' to Vlow1 and -Vlow1 alternately each time one screen is displayed.
- the luminance of all the pixels are restricted in comparison to the normal mode, as shown in Figure 5.
- the maximum luminance is reached and a white display is created when the potential difference of the pixels is Vhigh
- the low drive voltage display mode the maximum luminance is reached and a grayish display is created with reduced luminance in comparison to the normal mode when the potential difference of the pixels is Vlow1.
- the panel 230 can create displays while maintaining the relationship which exists in the normal mode between values of luminance data and the magnitude of luminance.
- the pixels in odd-numbered rows are displayed in black in Cycles 1 and 2, and the pixels in even-numbered rows are displayed in black in Cycles 3 and 4.
- the voltage supply section 250 sets the drive voltages VA and VB for odd-numbered rows to Vlow2 in Cycles 1 and 2 and sets the drive voltages VA and VB for even-numbered rows to Vlow2 in Cycles 3 and 4. Consequently, in displaying an image frame equivalent to one screen, the drive 255 sets the available range of the luminance for the pixels arranged in the even-numbered rows of the panel 230 such that it will be different from the available range of the luminance for the pixels arranged in the odd-numbered rows of the panel 230.
- the voltage supply section 250 sets the luminance of the pixels arranged in the even-numbered rows or odd-numbered rows of the panel 230 and used to display the image frame equivalent to one screen to black--a preset luminance.
- the pixels in odd-numbered columns are displayed in black in Cycles 1 and 2, and the pixels in even-numbered columns are displayed in black in Cycles 3 and 4.
- the voltage supply section 250 sets the drive voltage VB to Vlow2 in Cycles 1 and 2 and sets the drive voltage VA to Vlow2 in Cycles 3 and 4. Consequently, in displaying an image frame equivalent to one screen, the drive 255 sets the available range of the luminance for the pixels arranged in the even-numbered columns of the panel 230 such that it will be different from the available range of the luminance for the pixels arranged in the odd-numbered columns of the panel 230.
- the voltage supply section 250 sets the luminance of the pixels arranged in the even-numbered columns or odd-numbered columns of the panel 230 and used to display the image frame equivalent to one screen to black--a preset luminance.
- a checker display mode the pixels located at intersections of even-numbered rows and odd-numbered columns or at intersections of odd-numbered rows and even-numbered columns are displayed in black in Cycles 1 and 2, and the pixels located at intersections of even-numbered rows and even-numbered columns or at intersections of odd-numbered rows and odd-numbered columns are displayed in black in Cycles 3 and 4.
- the voltage supply section 250 sets the drive voltage VB for even-numbered rows and drive voltage VA for odd-numbered rows to Vlow2 in Cycles 1 and 2 and sets the drive voltage VA for even-numbered rows and drive voltage VB for odd-numbered rows to Vlow2 in Cycles 3 and 4.
- the drive 255 sets the available range of the luminance for the pixels located at intersections of even-numbered rows and odd-numbered columns or at intersections of odd-numbered rows and even-numbered columns in the panel 230 such that it will be different from the available range of the luminance for the pixels located at intersections of odd-numbered rows and odd-numbered columns or at intersections of even-numbered rows and even-numbered columns in the panel 230.
- the voltage supply section 250 sets the luminance of the pixels located at intersections of even-numbered rows and odd-numbered columns and at intersections of odd-numbered rows and even-numbered columns or at intersections of odd-numbered rows and odd-numbered columns and at intersections of even-numbered rows and even-numbered columns in the panel 230 and used to display the image frame equivalent to one screen to black--a preset luminance.
- the voltage supply section 250 changes the cycles of the alternating drive voltages VA' and VB' generated by the inverter circuit 423 and inverter circuit 426 in the source driver 270.
- the inverter circuit 423 and inverter circuit 426 set the alternating drive voltages VA' and VB' in Cycles 1 and 2 to Vhigh and set the alternating drive voltages VA' and VB' in Cycles 3 and 4 to -Vhigh based on instructions from the voltage supply section 250. Consequently, in the changed-inversion-cycle display mode, the drive 255 can make the polarity inversion cycle of the potential difference applied to pixels twice as long as in the normal mode.
- the display unit 200 may further comprise display modes consisting of combinations of low-power modes described above.
- it may further comprise a display mode consisting of a combination of the low drive voltage display mode and changed-inversion-cycle display mode.
- Figure 7 is a graph showing the potential differences applied to the pixels 310 according to this embodiment in each display mode.
- the horizontal axis represents time while the vertical axis represents the potential difference of specific pixels 310 in the panel 230.
- the potential difference of specific pixels 310 is set to either Vhigh or -Vhigh in every screen refresh.
- the potential difference of specific pixels 310 is set to either Vlow1 or -Vlow1 in every screen refresh.
- the voltage supply section 250 can narrow the range of potential difference applied to the pixels 310 in the panel 230 and lower the voltage used to drive the panel 230. Therefore, using the low drive voltage display mode, the display unit 200 can lower its power consumption compared to the normal mode.
- the display unit 200 may set Vlow1 to any value between 0 and Vhigh, inclusive, based on an instruction from the user of the information processing unit 100 or from the display control program running on the information processing unit 100. This will allow the user of the information processing unit 100 and the like to make appropriate trade-offs between easy screen viewing and low power consumption.
- the potential difference of specific pixels 310 is set to Vhigh in Cycle 1, to -Vhigh in Cycle 2, and 0 (or Vlow2) in Cycles 3 and 4.
- the voltage supply section 250 can narrow the range of potential difference applied to the pixels in the panel 230 and lower the voltage used to drive the panel 230. Therefore, using any of Modes 3 to 5, the display unit 200 can lower its power consumption compared to the normal mode.
- the display unit 200 may set the drive voltage(s) VA and/or VB for part of the pixels, for example, to Vlow1 based on an instruction from the user of the information processing unit 100 or from the display control program running on the information processing unit 100.
- Vlow1 may be set to any value between 0 and Vhigh, inclusive. This will allow the user of the information processing unit 100 and the like to make appropriate trade-offs between easy screen viewing and low power consumption.
- the display unit 200 may be configured such that it can set the number of the rows to be displayed in black to 3/4, 1/2, 1/4 of the total rows based on an instruction from the user of the information processing unit 100 or from the display control program running on the information processing unit 100.
- the potential difference of specific pixels 310 is set to Vhigh in Cycles 1 and 2, and to -Vhigh in Cycles 3 and 4.
- the drive 255 can make the polarity inversion cycle of the potential difference applied to pixels half as long as in the normal mode. Therefore, the display unit 200 can lower its power consumption compared to the normal mode.
- the display unit 200 may be configured such that it can vary the polarity inversion cycle of the potential difference applied to pixels based on an instruction from the user of the information processing unit 100 or from the display control program running on the information processing unit 100.
- Figure 8 shows a process flow of the display control program 180 running on the information processing unit 100.
- the instruction module 190 running on the information processing unit 100 sets the display mode of the display unit 200 to the normal mode (S800). If the display unit 200 is in a low-power display mode, the instruction module 190 instructs the mode setting module 185 to set the display mode to the normal mode. Based on the instruction from the instruction module 190, the mode setting module 185 sets the display mode to the normal mode. Specifically, the mode setting module 185 instructs the control circuit 210 to set the display mode of the display unit 200 to the normal mode. The control circuit 210 makes the display unit 200 set the normal mode either by informing the display unit 200 that no screen saving will be made at a screen-saving signal or by making the cycle of image data output to the display unit 200 shorter than that in the normal mode.
- the instruction module 190 running on the information processing unit 100 detects whether a condition for setting the display unit 200 to a low-power mode is satisfied (S810). If no input is entered in the information processing unit 100 from the user of the information processing unit 100 for a certain period of time or if the frequency at which the image memory 220 is updated by the CPU 110 in the information processing unit 100 or the like is lower than a preset value, the instruction module 190 determines that the condition for setting the display unit 200 to a low-power mode is satisfied.
- the instruction module 190 goes to S800 and proceeds with screen display in the normal mode (S820).
- the instruction module 190 instructs the mode setting module 185 to set the display mode to the low-power mode (S830). Based on the instruction from the instruction module 190, the mode setting module 185 sets the display mode to the low-power mode. Specifically, the mode setting module 185 instructs the control circuit 210 to set the display mode of the display unit 200 to the low-power mode.
- the control circuit 210 makes the display unit 200 set the low-power mode either by informing the display unit 200 that screen saving will be made at a screen-saving signal or by making the cycle of image data output to the display unit 200 longer than that in the normal mode.
- the image conversion module 195 converts the images displayed by the display unit 200, as required, so that the display unit 200 can operate at lower power (S840). For example, if the display unit 200 is not provided with the alternate-row display mode (Mode 3), alternate-column display mode (Mode 4), or checker display mode (Mode 5), the image conversion module 195 converts the image data in the image memory 220 so that the images stored in the image memory 220 will be approximately the same as the images displayed on the panel 230 in these modes. In other words, the image conversion module 195 changes the available range of the luminance for one part of the pixels forming the images displayed on the display unit 200 such that it will be different from the available range of the luminance for another part of the pixels forming the images. After the process in S840, the display control program 180 goes to S810.
- Figure 9 shows a configuration of the display unit 200 according to a variation of this embodiment.
- the display unit 200 according to the variation of this embodiment comprises a panel 231, signal receiver 235, data receiver 285, clock receiver 280, timing controller 290, mode setting section 240, current supply section 251, and drive 255 which in turn includes a gate driver 260 and source driver 271.
- the signal receiver 235, data receiver 285, clock receiver 280, timing controller 290, mode setting section 240, and gate driver 260 according to the variation of this embodiment are approximately the same as the corresponding components of the display unit 200 according to this embodiment shown in Figure 2, and thus description thereof will be omitted.
- the panel 231 has pixels arranged in a matrix.
- the panel 231 according to the variation of this embodiment sets the luminance of pixels according to the current applied to them.
- description will be given mainly of a normally black panel in which pixels are displayed in black when no current is applied to them.
- the panel 231 may be an organic EL or inorganic EL panel in which the luminance of pixels is set according to the current applied to them.
- the current supply section 251 supplies a current used to operate the drive 255. Also, the current supply section 251 changes a reference current for the current supplied to the panel 231 by the source driver 271 in the drive 255, in accordance with the display mode set by the mode setting section 240.
- the drive 255 drives the panel 231 based on image data to display the image data on the panel 231.
- the drive 255 includes the gate driver 260 and source driver 271.
- the gate driver 260 supplies a selection signal to a plurality of pixels arranged in the row direction on the panel 231.
- the source driver 271 supplies each of the pixels selected based on the selection signal from the gate driver 260 with a pixel drive current generated according to luminance data which specifies luminance of the given pixel and to the drive current from the current supply section 251.
- the display unit 200 of this embodiment can vary the drive voltage supplied to the source driver 270, according to the display mode of the display unit 200. This makes it possible to implement low-power modes for reducing the power consumption of the display unit 200 compared to the normal mode and/or extending the life of the display unit 200. Also, the display unit 200 allows the drive voltage which is supplied to the source driver 270 to be set to a value according to user preferences. This allows the user to specify a low-power mode of the display unit 200 appropriately by making appropriate trade-offs between easy screen viewing and low power consumption.
- the information processing unit 100 and display unit 200 allow the display mode of the display unit 200 to be specified according to the frequency of the data transfer clock. Consequently, the information processing unit 100 can slow the refresh rate, reduce the power consumption, and extend the life of the display unit 200 even if the display unit 200 is not provided with a low-power mode which corresponds to the frequency of the data transfer clock. Also, the display unit 200 can accept an instruction of specification of a display mode via the same one as an interface provided on a typical display or other display unit.
- the information processing unit 100 and/or display unit 200 can set the display unit 200 to a low-power mode which restricts the luminance range of pixels in comparison to the normal mode if there is no input from the user of the information processing unit 100 for a certain period of time. This makes it possible to set the display unit 200 to a low-power mode while the user of the information processing unit 100 is not operating the information processing unit 100, and thus to reduce the power consumption and extend the life of the display unit 200.
- the information processing unit 100 and/or display unit 200 can set the display unit 200 to a low-power mode which restricts the luminance range of pixels in comparison to the normal mode if the frequency at which the image memory 220 is updated in the information processing unit 100 or the like is lower than a preset value. This makes it possible to set the display unit 200 to a low-power mode while the user of the information processing unit 100 is not operating the information processing unit 100, and thus to reduce the power consumption and extend the life of the display unit 200.
- the information processing unit 100 and/or display unit 200 can set an available range of the luminance for one part of pixels used to form images displayed on the display unit in a low-power mode, such that it will be different from an available range of the luminance for another part of the pixels used to form the images. This makes it possible to lower the voltage used for driving one part of the pixels in the panel 230, and thus to reduce the power consumption and extend the life of the display unit 200.
- the display unit 200 can make the polarity inversion cycle of the potential difference which is applied to the pixels in the panel 230 in a low-power mode longer than that in the normal mode. This makes it possible to prolong the cycle of voltage fluctuations in the pixels in the panel 230, and thus to reduce the power consumption and extend the life of the display unit 200.
- the display unit 200 can vary the drive current supplied to the source driver 271, according to the display mode of the display unit 200. This makes it possible to implement low-power modes for reducing the power consumption of the display unit 200 compared to the normal mode and/or extending the life of the display unit 200. Also, the display unit 200 allows the drive current which is supplied to the source driver 271 to be set to a value according to user preferences. This allows the user to specify a low-power mode of the display unit 200 appropriately by making appropriate trade-offs between easy screen viewing and low power consumption.
Abstract
Description
- The present invention relates to a display unit, information processing unit, display method, and recording medium. More particularly, it relates to display unit or information processing unit equipped with a panel in which pixels are arranged in a matrix as well as to a related display method, program, or recording medium.
- Technologies for reducing power consumption of display units or extending the life of display units are disclosed, for example, in Japanese Published Unexamined Patent Applications No. 10-31464, No. 9-33888, and No. 5-323902, No. 10-124006.
- Japanese Published Unexamined Patent Application No. 10-31464 discloses a technology for reducing voltage fluctuations in output signals of scan line drivers feeding voltage to row direction pixels and data drivers feeding voltage to column direction pixels in an in-plane switching (IPS) liquid crystal display by providing two values--low and high--of potential to be applies to common lines feeding to all pixels and by reversing them on a frame by frame basis.
- Japanese Published Unexamined Patent Application No. 9-33888 discloses a liquid crystal display, which comprises a first drive mode for applying a selection voltage to each common electrode which feeds voltage to row direction pixels; a second drive mode for applying a selection voltage to each common electrode group organized along the column direction, wherein the second drive mode reduces power consumption.
- Japanese Published Unexamined Patent Application No. 5-323902 discloses a liquid crystal display which comprises a circuit for converting data by controlling external signals based on a predetermined law, in a data line drive circuit for supplying voltage to row direction pixels, and achieves long life by creating a display using converted display data.
- Japanese Published Unexamined Patent Application No. 10-124006 discloses a portable information terminal which automatically adjusts liquid crystal drive voltage in accordance with a bias ratio to achieve an optimum contrast ratio when the user adjusts the bias ratio of a liquid crystal display.
- It is desirable that a display unit, which visually displays information for the user, should allow the user to make appropriate trade-offs between easy screen viewing and low power consumption even in low-power mode such as power saving mode or life extension mode.
- Thus, a purpose of the present invention is to provide a display unit, information processing unit, display method, program, and recording medium which can solve the above problem. This purpose is served by a combination of features set forth in the independent claims herein. The dependent claims further present advantageous concrete examples of the present invention.
- Specifically, a first aspect of the present invention provides a display unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting a display mode of the above described display unit to one of a plurality of the above described display modes; a voltage supply section for changing a drive voltage which serves as a reference voltage for voltage supplied to the above described panel, according to the above described display mode set by the above described mode setting section; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage.
- The above described display unit may be a normally black display unit in which the luminance of the above described pixel decreases with decreases in a potential difference applied to the above described pixel by the above described pixel drive voltage.
- Also, a second aspect of the present invention provides a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, including: a data receiver for receiving an image frame which corresponds to one screen of image data from outside at preset intervals; a drive for setting luminance for each of the above described plurality of pixels in the above described panel and displaying the above described image on the above described panel; and a mode setting section for setting the above described display unit to one of display modes, including a normal mode which makes the above described display unit create a normal display and a restricted mode, wherein in the above described restricted mode, the above described drive sets an available range of the above described luminance for one part of the above described pixels used to display the above described image frame such that it will be different from an available range of the above described luminance for another part of the above described pixels used to display the above described image frame.
- Also, a third aspect of the present invention provides a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, including: a drive for supplying each of the above described plurality of pixels in the above described panel with a voltage for setting luminance for the pixel; and a mode setting section for setting the above described display unit to one of display modes, including a normal mode which makes the above described display unit create a normal display and a restricted mode, wherein the above described drive periodically reverses polarity of a potential difference applied to the above described pixel by the above described pixel drive voltage, and the above described drive sets the cycle of polarity reversal of the above described potential difference applied to the above described pixel in the above described restricted mode such that it will be longer than that in the above described normal mode.
- Also, a fourth aspect of the present invention provides a display unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting a display mode of the above described display unit to one of a plurality of the above described display modes; a current supply section for changing a drive current which serves as a reference current for current supplied to the above described panel, according to the above described display mode set by the above described mode setting section; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive current generated according to luminance data which specifies luminance of the given pixel and to the above described drive current.
- Also, a fifth aspect of the present invention provides an information processing unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting the above described panel to one of display modes, including a normal mode which makes the above described panel create a normal display and a restricted mode which restricts a luminance range of the above described pixels in comparison to the above described normal mode; an instruction section for making the above described panel set the above described display mode to the above described restricted mode upon fulfillment of the necessary condition that there is no user input for a certain period of time; a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel and restricting a luminance range of the above described pixels in comparison to the above described normal mode when the above described restricted mode is entered; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage.
- Also, a sixth aspect of the present invention provides an information processing unit equipped with a panel in which pixels are arranged in a matrix, including: a mode setting section for setting the above described panel to one of display modes, including a normal mode which makes the above described panel create a normal display and a restricted mode which restricts a luminance range of the above described pixels in comparison to the above described normal mode; an instruction section for making the above described panel set the above described display mode to the above described restricted mode upon fulfillment of the necessary condition that the frequency at which the above described image memory is updated is lower than a preset value; a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel and restricting a luminance range of the above described pixels in comparison to the above described normal mode when the above described restricted mode is entered; a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel; and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage.
- Also, a seventh aspect of the present invention provides a display method for controlling a display unit equipped with a panel in which pixels are arranged in a matrix, a voltage supply section for supplying a drive voltage which serves as a reference voltage for voltage supplied to the above described panel, a gate driver for supplying a selection signal to a plurality of the above described pixels arranged in the row direction on the above described panel, and a source driver for supplying each of the above described plurality of pixels selected based on the above described selection signal with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the above described drive voltage, the above described display method including the steps of: setting the above described display unit to one of a plurality of display modes; and changing the above described drive voltage according to the above described display mode selected.
- Also, an eighth aspect of the present invention provides a program for an information processing unit, the above described program controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein: the above described information processing unit outputs luminance data of a plurality of the above described pixels which form images to the above described display unit and thereby displays the above described images on the above described display unit; and the above described program comprises a mode setting module for making the above described information processing unit set the above described display mode of the above described display unit to either a normal mode in which the above described display unit creates a normal display or a low-power mode which reduces power consumption of the above described display unit compared to the above described normal mode, and set frequency at which the above described information processing unit outputs the above described luminance data in the above described low-power mode such that it will be lower than that in the above described normal mode.
- Also, a ninth aspect of the present invention provides a storage medium containing a program for an information processing unit, the above described program controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein: the above described information processing unit outputs luminance data of a plurality of the above described pixels which form images to the above described display unit and thereby displays the above described images on the above described display unit; and the above described program comprises a mode setting module for making the above described information processing unit set the above described display mode of the above described display unit to either a normal mode in which the above described display unit creates a normal display or a low-power mode which reduces power consumption of the above described display unit compared to the above described normal mode, and set frequency at which the above described information processing unit outputs the above described luminance data in the above described low-power mode such that it will be lower than that in the above described normal mode.
- Also, a tenth aspect of the present invention provides a program for controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein the above described display unit includes: a mode setting module for making the above described display unit set itself to one of display modes, including a normal mode in which the above described display unit creates a normal display and a restricted mode; and an image conversion module for making the above described display unit convert, in the above described restricted mode, an available range of the above described luminance for one part of the above described pixels used to form an image displayed on the above described display unit, such that it will be different from an available range of the above described luminance for another part of the above described pixels used to form the above described image.
- Also, an eleventh aspect of the present invention provides a storage medium containing a program for controlling a display unit equipped with a panel in which a plurality of pixels are arranged in a matrix, wherein the above described program includes on the above described display unit: a mode setting module for making the above described display unit set itself to one of display modes, including a normal mode in which the above described display unit creates a normal display and a restricted mode; and an image conversion module for making the above described display unit convert, in the above described restricted mode, an available range of the above described luminance for one part of the above described pixels used to form an image displayed on the above described display unit, such that it will be different from an available range of the above described luminance for another part of the above described pixels used to form the above described image.
- Some of the purposes of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:
- Figure 1 is a diagram showing a configuration of an
information processing unit 100 according to an embodiment of the present invention; - Figure 2 is a diagram showing a configuration of an
output device 150 according to the embodiment of the present invention; - Figure 3 is a diagram showing a configuration of a
panel 230 according to the embodiment of the present invention; - Figure 4 is a diagram showing a configuration of a
source driver 270 according to the embodiment of the present invention; - Figure 5 is a graph of relationship between potential differences applied to
pixels 310 and luminance of thepixels 310 according to the embodiment of the present invention; - Figure 6 is a diagram showing display modes set by a
mode setting part 240 in a tabular form, according to the embodiment of the present invention; - Figure 7 is a graph showing potential differences applied to the
pixels 310 in each display mode according to the embodiment of the present invention; - Figure 8 is a diagram showing a process flow of a
display control program 180 running on theinformation processing unit 100 according to the embodiment of the present invention; and - Figure 9 is a diagram showing a configuration of a
display unit 200 according to a variation of the embodiment of the present invention. - While the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the present invention is shown, it is to be understood at the outset of the description which follows that persons of skill in the appropriate arts may modify the invention here described while still achieving the favorable results of the invention. Accordingly, the description which follows is to be understood as being a broad, teaching disclosure directed to persons of skill in the appropriate arts, and not as limiting upon the present invention.
- Figure 1 shows a configuration of an
information processing unit 100 according to this embodiment. The information processing unit according to thisembodiment 100 comprises aCPU 110,ROM 115,RAM 120,communications interface 125,hard disk drive 130,floppy disk drive 135, CD-ROM drive 140,input device 145,output device 150,system control circuit 155, and input/output bus 160. - The
CPU 110 operates based on programs stored on theROM 115 andRAM 120 and controls various components. Thecommunications interface 125 communicates with other devices via a network. Thehard disk drive 130 stores programs and data used by theinformation processing unit 100 and supplies programs to theRAM 120 based on instructions from the user of theinformation processing unit 100. Thefloppy disk drive 135 reads programs or data from afloppy disk 165 and supplies them to theRAM 120. The CD-ROM drive 140 reads programs or data from a CD-ROM 170 and supplies them to theRAM 120. Theinput device 145 allows the user of theinformation processing unit 100 to enter instructions. Theoutput device 150 displays images, including characters and/or graphics, for the user, based on instructions from programs operating on theinformation processing unit 100. Thesystem control circuit 155 connects theCPU 110,ROM 115,RAM 120,communications interface 125,hard disk drive 130,floppy disk drive 135, CD-ROM drive 140,input device 145, andoutput device 150 with each other. The input/output bus 160 connects thesystem control circuit 155 with thecommunications interface 125,hard disk drive 130,floppy disk drive 135, CD-ROM drive 140,input device 145, andoutput device 150. - The
hard disk drive 130 stores adisplay control program 180 which runs on theCPU 110. Thedisplay control program 180 is started by the user or by the operating system which runs on theinformation processing unit 100. It controls theoutput device 150. Thedisplay control program 180 includes amode setting module 185,instruction module 190, andimage conversion module 195. These modules are programs which make theinformation processing unit 100 operate as a mode setting section, instruction section, and image conversion section on theinformation processing unit 100. Themode setting module 185 sets display mode of a display unit in theoutput device 150 to either a normal mode for normal display or a low-power mode intended to reduce power consumption and extend the life of the display unit. The low-power mode is an example of reduced mode according to the present invention. Theinstruction module 190 instructs themode setting module 185 to set the display mode to the low-power mode upon fulfillment of preset conditions. Theinstruction module 190 may, for example, monitor theinput device 145 and make theoutput device 150 go into the low-power mode upon fulfillment of the necessary condition that there is no user input for a certain period of time. When the display mode of the display unit in theoutput device 150 is set to the low-power mode, theimage conversion module 195 converts, as required, images displayed by the display unit in theoutput device 150 so that the display unit in theoutput device 150 can operate at lower power. - The
display control program 180 is supplied by the user, being stored on a recording medium such as thefloppy disk 165 or CD-ROM 170. Thedisplay control program 180 is read from the recording medium, installed in theinformation processing unit 100 via thefloppy disk drive 135 or CD-ROM drive 140, and executed on theinformation processing unit 100. - The programs or modules described above may be stored on an external storage medium. In addition to the
floppy disk 165 and CD-ROM 170, various storage media are available including optical recording media such as a DVD and PD, magneto-optical recording media such as an MO, tape media, and semiconductor memories such as an IC card. Alternatively, the programs may be supplied to theinformation processing unit 100 via a dedicated communications network or the Internet using a hard disk, RAM, or other storage device which serves as a recording medium having been installed in a server system connected to the network. Figure 2 shows a configuration of theoutput device 150 according to this embodiment. Theoutput device 150 according to this embodiment comprises adisplay unit 200,control circuit 210, andimage memory 220. - The
display unit 200 displays images, including characters and/or graphics, for the user, based on instructions from programs operating on theinformation processing unit 100. - The
control circuit 210 controls thedisplay unit 200 as well as theimage memory 220 which stores luminance data of each pixel in image data, and thereby carries out an image data storage process, image data output process, and display mode setting process. - In the image data storage process, the
control circuit 210 receives data which composes images from theCPU 110 via thesystem control circuit 155 and stores it in theimage memory 220 as image data which includes the luminance of each pixel on screen. In this process, thecontrol circuit 210 may calculate the luminance of each pixel based on information about objects such as rectangles and points which compose the images by receiving it from theCPU 110. Alternatively, thecontrol circuit 210 may directly receive addresses on theimage memory 220 and write data from theCPU 110 and store the write data at the appropriate addresses in theimage memory 220. - In the image data output process, the
control circuit 210 reads the luminance data of each pixel in the image data from theimage memory 220 and transmits it in sequence to thedisplay unit 200. When transmitting the luminance data, thecontrol circuit 210 outputs a data transfer clock to thedisplay unit 200 in synchronization with a data signal for outputting the luminance data of each pixel to thedisplay unit 200. - In the display mode setting process, the
control circuit 210 sets the display mode of thedisplay unit 200 to either the normal mode or low-power mode based on the setting of themode setting module 185 which runs on theCPU 110. To set the display mode of thedisplay unit 200 to the low-power mode, thecontrol circuit 210 at least outputs a screen-saving signal instructing thedisplay unit 200 to enter the low-power mode or prolongs the cycle of image data output to thedisplay unit 200. When prolonging the cycle of image data output to thedisplay unit 200, thecontrol circuit 210 lengthens the time required to transmit the luminance data of each pixel to thedisplay unit 200 and lowers the frequency of the data transfer clock. - Next, a configuration of the
display unit 200 will be described. Thedisplay unit 200 comprises apanel 230,signal receiver 235,data receiver 285,clock receiver 280,timing controller 290,mode setting section 240,voltage supply section 250, and drive 255. - The
panel 230 has pixels arranged in a matrix. Thepanel 230 according to this embodiment is a liquid crystal panel on which the luminance of pixels is set according to potential differences applied to them. It is a normally black type on which pixels are displayed in black when no potential difference is applied to them. Thepanel 230 may be a liquid crystal panel which employs AFLC technology, MIM elements, TFT-based OCB mode, IPS mode, or MVA mode. Also, thepanel 230 may be a display panel other than a liquid crystal panel which sets the luminance of pixels according to potential differences applied to them. Furthermore, thepanel 230 may be a normally white type in which pixels are displayed in white when no potential difference is applied to them. - The
signal receiver 235 receives a screen-saving signal outputted by theoutput device 150 in thecontrol circuit 210 upon fulfillment of the necessary condition that there is no user input for a certain period of time. Thedata receiver 285 receives the luminance data of each pixel in the image data as a data signal from thecontrol circuit 210. Theclock receiver 280 receives the data transfer clock inputted in synchronization with the data signal for inputting the luminance data. Based on the data transfer clock received by theclock receiver 280, thetiming controller 290 outputs, to thegate driver 260 andsource driver 270, timing signals for driving them. Also, thetiming controller 290 outputs the luminance data to thesource driver 270 in synchronization with the timing signals. - The
mode setting section 240 sets the display mode of thedisplay unit 200 to the low-power mode if thesignal receiver 235 receives a screen-saving signal and/or if theclock receiver 280 receives a data transfer clock with a lower frequency than that in the normal mode. On the other hand, if the conditions setting for the low-power mode are not satisfied, themode setting section 240 sets the display mode of thedisplay unit 200 to the normal mode. - The
mode setting section 240 sets six display modes for the display unit 200:Modes 1 to 6.Mode 1 is a display mode which makes thedisplay unit 200 create a normal display.Modes 2 to 6 are display modes which make thedisplay unit 200 create a low-power display. Of the low-power modes,Mode 2 is a low drive voltage display mode. In the low drive voltage display mode, themode setting section 240 makes thevoltage supply section 250 supply thesource driver 270 with a drive voltage which restricts the luminance range of pixels on thepanel 230 in comparison to the normal mode. To set a low-power mode, themode setting section 240 selects one of the five low-power display mode based on a setting specified by the user of theinformation processing unit 100 and/or an instruction from the display control program. - The
voltage supply section 250 supplies voltage used to operate thedrive 255. Also, thevoltage supply section 250 changes a reference voltage for the voltage supplied to thepanel 230 by thesource driver 270 in thedrive 255, in accordance with the display mode set by themode setting section 240. - The
drive 255 drives thepanel 230 based on image data to display the image data on thepanel 230. Thedrive 255 includes thegate driver 260 andsource driver 270. Thegate driver 260 supplies a selection signal to a plurality of pixels arranged in the row direction on thepanel 230. Thesource driver 270 supplies each of the pixels selected based on the selection signal from thegate driver 260 with a pixel drive voltage generated according to luminance data which specifies luminance of the given pixel and to the drive voltage from thevoltage supply section 250. - Figure 3 shows a configuration of the
panel 230 according to this embodiment. In thepanel 230 according to this embodiment, pixels each of which contains apixel 310 andcorresponding switching element 300 are arranged in the row and column directions. - The
switching element 300 switches on when a selection signal VGy (where y = 0, 1, ..., m) from thegate driver 260 is High (H Level). When theswitching element 300 switches on, a pixel drive voltage VDx (where x = 0, 1, ..., n) is supplied to thepixel 310 in the corresponding pixel. - The
pixel 310 sets its luminance based on the potential difference between the pixel drive voltage VDx and a common voltage Vcom. When theswitching element 300 switches off again, thepixel 310 functions also as a capacitor which retains the supplied pixel drive voltage VDx. - The
gate driver 260 andsource driver 270 display an image frame constituted by one page of image data on thepanel 230 as follows. First, thesource driver 270 receives one row of luminance data from thecontrol circuit 210. Next, thegate driver 260 sets the selection signal VGy of the pixels arranged in the given row (y-th row) to High. This turns on the switchingelements 300 of the pixels arranged in the y-th row. Then, thesource driver 270 supplies the appropriate pixel drive voltage VDx (in the case of the x-th column) to each of the pixels selected by the selection signal. Consequently, thepixels 310 in the pixels arranged in the y-th row are supplied with the corresponding VD0 to VDn. Then, thegate driver 260 sets the selection signal VGy of the pixels arranged in the y-th row to Low (L Level). This turns off the switchingelements 300 of the pixels arranged in the y-th row. Consequently, the pixels arranged in the y-th row retain VD0 to VDn supplied to them. The above operations allow thegate driver 260 andsource driver 270 to set the luminance of the pixels arranged in the y-th row. - Next, the
gate driver 260 andsource driver 270 set the luminance of the (y + 1)th pixel in a manner similar to the one described above. By performing this operation for all the rows on one screen, thedisplay unit 200 can display one screen of image data. - According to this embodiment, it is assumed for the convenience of description that the
panel 230 displays each pixel in eight gradations. Also, it is assumed that the luminance data received by thedisplay unit 200 from thecontrol circuit 210 via a data signal is one ofinteger values 0 to 7. Incidentally, thedisplay unit 200 according to this embodiment may use less than or more than eight gradations for display on thepanel 230. - Although the
panel 230 is driven in relation to the row and column directions, the rows and columns according to this embodiment may be independent of the up, down, left, and right directions of the image shown to the user. For example, theinformation processing unit 100 may display images on thepanel 230 in such a way that the vertical direction of the images coincide with the column direction of thepanel 230 or in such a way that the horizontal direction of the images coincide with the column direction of thepanel 230. - Figure 4 shows a configuration of the
source driver 270 according to this embodiment. -Thesource driver 270 according to this embodiment comprises, ashift register 400,sampling memories 410a to 410c, holdingmemories 420a to 420c, aninverter circuit 423, aninverter circuit 426, atransformer circuit 430, atransformer circuit 440, andoutput circuits 450a to 450c. - The
shift register 400 receives a timing signal which includes a start signal and data transfer clock from thetiming controller 290. The start signal specifies, using H Level, when to start sending out luminance data for one row of pixels to thesource driver 270. By using these timing signals, theshift register 400 sends out a clock ck to thesampling memory 410a while receiving the luminance data for the 0-th row from the data signal, sends out a clock ck to thesampling memory 410b while receiving the luminance data for the 1st row from the data signal, ..., and sends out a clock ck to thesampling memory 410c while receiving the luminance data for the last row from the data signal. - Upon receiving the clock ck from the
shift register 400, thesampling memories 410a to 410c store the luminance data contained in the data signal. Then, thesampling memories 410a to 410c output the stored luminance data to the corresponding holdingmemories 420a to 420c. In this way, upon receiving the luminance data for one row of pixels from thetiming controller 290, thesampling memories 410a to 410c output the luminance data of the pixels at the respective locations. - The holding
memories 420a to 420c store the luminance data outputted by the correspondingsampling memories 410a to 410c when a line display signal received from thetiming controller 290 becomes High level. Then, the holdingmemories 420a to 420c output the stored luminance data to thecorresponding output circuits 450a to 450c. When the luminance data for one row of pixels has been transmitted, thetiming controller 290 sets the line display signal to High. Consequently, when thesource driver 270 receives the luminance data for one row of pixels, the holdingmemories 420a to 420c output the luminance data for one row of pixels in synchronization with the line display signal. - To invert the polarity of voltage applied to each pixel in even-numbered rows in the
panel 230, theinverter circuit 423 generates an alternating drive voltage VA' by alternately inverting a drive voltage VA with respect to Vcom. Similarly, to invert the polarity of a voltage applied to each pixel in odd-numbered rows in thepanel 230, theinverter circuit 426 generates an alternating drive voltage VB' by alternately inverting a drive voltage VB with respect to Vcom. Theinverter circuit 423 andinverter circuit 426 set the inversion cycles of VA and VB, respectively, by receiving them from thevoltage supply section 250. - The
transformer circuit 430 generates pixel drive voltages VA0 to VA7 to be supplied to thepanel 230, using the alternating drive voltage VA' received from theinverter circuit 423 as a reference voltage. Here, VA0 to VA7 are pixel drive voltages which correspond to theluminance data values 0 to 7. Similarly, thetransformer circuit 440 generates pixel drive voltages VB0 to VB7 to be supplied to thepanel 230, using the alternating drive voltage VB' received from thevoltage supply section 250 as a reference voltage. - According to the luminance data received from the corresponding holding
memories 420a to 420c, theoutput circuits 450a to 450c select the pixel drive voltages VA0 to VA7 or pixel drive voltages VB0 to VB7 and supply them to VD0 to VDn. The output circuits such as 450a for the even-numbered rows select respective pixel drive voltages from VA0 to VA7. On the other hand, the output circuits such as 450b and 450c for the odd-numbered rows select pixel drive voltages from VB0 to VB7. - Figure 5 shows a graph of the relationship between potential differences applied to the
pixels 310 and luminance of thepixels 310 according to this embodiment. In the graph of Figure 5, the horizontal axis represents the potential difference applied to thepixels 310 and the vertical axis represents the luminance of thepixels 310. - The solid line in Figure 5 represents the relationship between potential difference and luminance for a normally black type in which pixels are displayed in black when no potential difference is applied to them.
- In the case of the normally black type (solid line), pixels are displayed in black when the potential differences applied to them are no higher than Vlow2 and they are displayed in white when the potential differences applied to them are no lower than Vhigh. On the normally black type display unit, the luminance of the pixels is reduced with decreases in the potential differences applied to the pixels by the pixel drive voltages.
- In the normal mode which makes the
display unit 200 create a normal display, thevoltage supply section 250 sets VA and VB to Vhigh. In the normal mode, thesource driver 270 outputs pixel drive voltages with a potential difference in the range of Vlow2 to Vhigh to thepanel 230. - On the other hand, in the low drive voltage display mode, which reduces power consumption of the
display unit 200 compared to the normal mode, thevoltage supply section 250 sets VA and/or VB to Vlow1. Thesource driver 270 outputs pixel drive voltages with a potential difference in the range of Vlow2 to Vlow1 to thepanel 230. By setting the drive voltage(s) VA and/or VB to Vlow1, thevoltage supply section 250 can set the drive voltage(s) VA and/or VB in the low drive voltage display mode at a level lower than those for the maximum luminance of the pixels in the normal mode. Also, by setting the drive voltage(s) VA and/or VB to Vlow1, thevoltage supply section 250 can reduce the range of potential difference applied to thepanel 230 and lower the voltage used to drive thepanel 230, and thereby reduce the power consumption of thedisplay unit 200 compared to the normal mode. - The broken line in Figure 5 represents the relationship between potential difference and luminance for a normally white type in which pixels are displayed in white when no potential difference is applied to them.
- In the case of the normally white type (broken line), pixels are displayed in black when the potential differences applied to them are VWhigh and they are displayed in white when the potential differences applied to them are VWlow2. On the normally white type display unit, the luminance of the pixels increases with decreases in the pixel drive voltages.
- In the normal mode which makes the
display unit 200 create a normal display, thevoltage supply section 250 sets VA and VB to VWlow2. In the normal mode, thesource driver 270 outputs pixel drive voltages with a potential difference in the range of VWhigh to VWlow2 to thepanel 230. - On the other hand, in the low-power modes, which reduce power consumption of the
display unit 200 compared to the normal mode, thevoltage supply section 250 may set VA and/or VB to VWlow1. In this case, thesource driver 270 outputs pixel drive voltages with a potential difference in the range of VWhigh to VWlow1 to thepanel 230. By setting the drive voltage(s) VA and/or VB to VWlow1, thevoltage supply section 250 can set the drive voltage(s) VA and/or VB in the low-power modes at a level lower than those for the maximum luminance of the pixels in the normal mode. Also, by setting the drive voltage(s) VA and/or VB to VWlow1, thevoltage supply section 250 can reduce the range of potential difference applied to thepanel 230, and in conjunction, for example, with a method for prolonging the inversion cycle of theinverter circuit 423 and/orinverter circuit 426, it can reduce the power consumption of thedisplay unit 200 compared to the normal mode. - Figure 6 shows the display modes set by the
mode setting section 240 according to this embodiment in a tabular form. Themode setting section 240 according to this embodiment has the six display modes--Mode 1 toMode 6--shown in Figure 6.Mode 1 is the normal mode whileMode 2 toMode 6 are low-power modes different from each other. Figure 6 shows, for each ofMode 1 toMode 6, transitions of the alternating drive voltages VA' and VB' outputted by theinverter circuit 423 andinverter circuit 426 during each cycle in which thedisplay unit 200 displays one screen. - In the normal mode, the
voltage supply section 250 supplies Vhigh to the drive voltages VA and VB. In response, theinverter circuit 423 andinverter circuit 426 sets both VA' and VB' alternately to Vhigh and -Vhigh each time one screen is displayed. - In the low drive voltage display mode, the
voltage supply section 250 sets Vlow1 to the drive voltages VA and VB. In response, theinverter circuit 423 andinverter circuit 426 set both VA' and VB' to Vlow1 and -Vlow1 alternately each time one screen is displayed. Thus, in the low drive voltage display mode, the luminance of all the pixels are restricted in comparison to the normal mode, as shown in Figure 5. Specifically, whereas in the normal mode, the maximum luminance is reached and a white display is created when the potential difference of the pixels is Vhigh, in the low drive voltage display mode, the maximum luminance is reached and a grayish display is created with reduced luminance in comparison to the normal mode when the potential difference of the pixels is Vlow1. On the other hand, even in the low drive voltage display mode, thepanel 230 can create displays while maintaining the relationship which exists in the normal mode between values of luminance data and the magnitude of luminance. - In an alternate-row display mode, the pixels in odd-numbered rows are displayed in black in
Cycles Cycles voltage supply section 250 sets the drive voltages VA and VB for odd-numbered rows to Vlow2 inCycles Cycles drive 255 sets the available range of the luminance for the pixels arranged in the even-numbered rows of thepanel 230 such that it will be different from the available range of the luminance for the pixels arranged in the odd-numbered rows of thepanel 230. Also, in the alternate-row display mode according to this embodiment, thevoltage supply section 250 sets the luminance of the pixels arranged in the even-numbered rows or odd-numbered rows of thepanel 230 and used to display the image frame equivalent to one screen to black--a preset luminance. - In an alternate-column display mode, the pixels in odd-numbered columns are displayed in black in
Cycles Cycles voltage supply section 250 sets the drive voltage VB to Vlow2 inCycles Cycles drive 255 sets the available range of the luminance for the pixels arranged in the even-numbered columns of thepanel 230 such that it will be different from the available range of the luminance for the pixels arranged in the odd-numbered columns of thepanel 230. Also, in the alternate-column display mode according to this embodiment, thevoltage supply section 250 sets the luminance of the pixels arranged in the even-numbered columns or odd-numbered columns of thepanel 230 and used to display the image frame equivalent to one screen to black--a preset luminance. - In a checker display mode, the pixels located at intersections of even-numbered rows and odd-numbered columns or at intersections of odd-numbered rows and even-numbered columns are displayed in black in
Cycles Cycles voltage supply section 250 sets the drive voltage VB for even-numbered rows and drive voltage VA for odd-numbered rows to Vlow2 inCycles Cycles drive 255 sets the available range of the luminance for the pixels located at intersections of even-numbered rows and odd-numbered columns or at intersections of odd-numbered rows and even-numbered columns in thepanel 230 such that it will be different from the available range of the luminance for the pixels located at intersections of odd-numbered rows and odd-numbered columns or at intersections of even-numbered rows and even-numbered columns in thepanel 230. Also, in the checker display mode according to this embodiment, thevoltage supply section 250 sets the luminance of the pixels located at intersections of even-numbered rows and odd-numbered columns and at intersections of odd-numbered rows and even-numbered columns or at intersections of odd-numbered rows and odd-numbered columns and at intersections of even-numbered rows and even-numbered columns in thepanel 230 and used to display the image frame equivalent to one screen to black--a preset luminance. - In a changed-inversion-cycle display mode, the
voltage supply section 250 changes the cycles of the alternating drive voltages VA' and VB' generated by theinverter circuit 423 andinverter circuit 426 in thesource driver 270. Specifically, in the changed-inversion-cycle display mode, theinverter circuit 423 andinverter circuit 426 set the alternating drive voltages VA' and VB' inCycles Cycles voltage supply section 250. Consequently, in the changed-inversion-cycle display mode, thedrive 255 can make the polarity inversion cycle of the potential difference applied to pixels twice as long as in the normal mode. - The
display unit 200 according to this embodiment may further comprise display modes consisting of combinations of low-power modes described above. For example, it may further comprise a display mode consisting of a combination of the low drive voltage display mode and changed-inversion-cycle display mode. - Figure 7 is a graph showing the potential differences applied to the
pixels 310 according to this embodiment in each display mode. In the figure, the horizontal axis represents time while the vertical axis represents the potential difference ofspecific pixels 310 in thepanel 230. - In the normal mode (Mode 1), the potential difference of
specific pixels 310 is set to either Vhigh or -Vhigh in every screen refresh. - In the low drive voltage display mode (Mode 2), the potential difference of
specific pixels 310 is set to either Vlow1 or -Vlow1 in every screen refresh. In this way, in the low drive voltage display mode, thevoltage supply section 250 can narrow the range of potential difference applied to thepixels 310 in thepanel 230 and lower the voltage used to drive thepanel 230. Therefore, using the low drive voltage display mode, thedisplay unit 200 can lower its power consumption compared to the normal mode. - Incidentally, the
display unit 200 may set Vlow1 to any value between 0 and Vhigh, inclusive, based on an instruction from the user of theinformation processing unit 100 or from the display control program running on theinformation processing unit 100. This will allow the user of theinformation processing unit 100 and the like to make appropriate trade-offs between easy screen viewing and low power consumption. - In the alternate-row display mode (Mode 3), alternate-column display mode (Mode 4), and checker display mode (Mode 5), the potential difference of
specific pixels 310 is set to Vhigh inCycle 1, to -Vhigh inCycle 2, and 0 (or Vlow2) inCycles Modes 3 to 5, thevoltage supply section 250 can narrow the range of potential difference applied to the pixels in thepanel 230 and lower the voltage used to drive thepanel 230. Therefore, using any ofModes 3 to 5, thedisplay unit 200 can lower its power consumption compared to the normal mode. - Incidentally, the
display unit 200 may set the drive voltage(s) VA and/or VB for part of the pixels, for example, to Vlow1 based on an instruction from the user of theinformation processing unit 100 or from the display control program running on theinformation processing unit 100. In that case, Vlow1 may be set to any value between 0 and Vhigh, inclusive. This will allow the user of theinformation processing unit 100 and the like to make appropriate trade-offs between easy screen viewing and low power consumption. - Also, the
display unit 200 may be configured such that it can set the number of the rows to be displayed in black to 3/4, 1/2, 1/4 of the total rows based on an instruction from the user of theinformation processing unit 100 or from the display control program running on theinformation processing unit 100. - In the changed-inversion-cycle display mode (Mode 6), the potential difference of
specific pixels 310 is set to Vhigh inCycles Cycles drive 255 can make the polarity inversion cycle of the potential difference applied to pixels half as long as in the normal mode. Therefore, thedisplay unit 200 can lower its power consumption compared to the normal mode. - Also, the
display unit 200 may be configured such that it can vary the polarity inversion cycle of the potential difference applied to pixels based on an instruction from the user of theinformation processing unit 100 or from the display control program running on theinformation processing unit 100. - Figure 8 shows a process flow of the
display control program 180 running on theinformation processing unit 100. - First, the
instruction module 190 running on theinformation processing unit 100 sets the display mode of thedisplay unit 200 to the normal mode (S800). If thedisplay unit 200 is in a low-power display mode, theinstruction module 190 instructs themode setting module 185 to set the display mode to the normal mode. Based on the instruction from theinstruction module 190, themode setting module 185 sets the display mode to the normal mode. Specifically, themode setting module 185 instructs thecontrol circuit 210 to set the display mode of thedisplay unit 200 to the normal mode. Thecontrol circuit 210 makes thedisplay unit 200 set the normal mode either by informing thedisplay unit 200 that no screen saving will be made at a screen-saving signal or by making the cycle of image data output to thedisplay unit 200 shorter than that in the normal mode. - Next, the
instruction module 190 running on theinformation processing unit 100 detects whether a condition for setting thedisplay unit 200 to a low-power mode is satisfied (S810). If no input is entered in theinformation processing unit 100 from the user of theinformation processing unit 100 for a certain period of time or if the frequency at which theimage memory 220 is updated by theCPU 110 in theinformation processing unit 100 or the like is lower than a preset value, theinstruction module 190 determines that the condition for setting thedisplay unit 200 to a low-power mode is satisfied. - If the condition for setting the
display unit 200 to a low-power mode is not satisfied, theinstruction module 190 goes to S800 and proceeds with screen display in the normal mode (S820). - If the condition for setting the
display unit 200 to a low-power mode is satisfied, theinstruction module 190 instructs themode setting module 185 to set the display mode to the low-power mode (S830). Based on the instruction from theinstruction module 190, themode setting module 185 sets the display mode to the low-power mode. Specifically, themode setting module 185 instructs thecontrol circuit 210 to set the display mode of thedisplay unit 200 to the low-power mode. Thecontrol circuit 210 makes thedisplay unit 200 set the low-power mode either by informing thedisplay unit 200 that screen saving will be made at a screen-saving signal or by making the cycle of image data output to thedisplay unit 200 longer than that in the normal mode. - Next, the
image conversion module 195 converts the images displayed by thedisplay unit 200, as required, so that thedisplay unit 200 can operate at lower power (S840). For example, if thedisplay unit 200 is not provided with the alternate-row display mode (Mode 3), alternate-column display mode (Mode 4), or checker display mode (Mode 5), theimage conversion module 195 converts the image data in theimage memory 220 so that the images stored in theimage memory 220 will be approximately the same as the images displayed on thepanel 230 in these modes. In other words, theimage conversion module 195 changes the available range of the luminance for one part of the pixels forming the images displayed on thedisplay unit 200 such that it will be different from the available range of the luminance for another part of the pixels forming the images. After the process in S840, thedisplay control program 180 goes to S810. - Figure 9 shows a configuration of the
display unit 200 according to a variation of this embodiment. Thedisplay unit 200 according to the variation of this embodiment comprises apanel 231,signal receiver 235,data receiver 285,clock receiver 280,timing controller 290,mode setting section 240,current supply section 251, and drive 255 which in turn includes agate driver 260 andsource driver 271. Thesignal receiver 235,data receiver 285,clock receiver 280,timing controller 290,mode setting section 240, andgate driver 260 according to the variation of this embodiment are approximately the same as the corresponding components of thedisplay unit 200 according to this embodiment shown in Figure 2, and thus description thereof will be omitted. - The
panel 231 has pixels arranged in a matrix. Thepanel 231 according to the variation of this embodiment sets the luminance of pixels according to the current applied to them. Here, description will be given mainly of a normally black panel in which pixels are displayed in black when no current is applied to them. Thepanel 231 may be an organic EL or inorganic EL panel in which the luminance of pixels is set according to the current applied to them. - The
current supply section 251 supplies a current used to operate thedrive 255. Also, thecurrent supply section 251 changes a reference current for the current supplied to thepanel 231 by thesource driver 271 in thedrive 255, in accordance with the display mode set by themode setting section 240. - The
drive 255 drives thepanel 231 based on image data to display the image data on thepanel 231. Thedrive 255 includes thegate driver 260 andsource driver 271. Thegate driver 260 supplies a selection signal to a plurality of pixels arranged in the row direction on thepanel 231. Thesource driver 271 supplies each of the pixels selected based on the selection signal from thegate driver 260 with a pixel drive current generated according to luminance data which specifies luminance of the given pixel and to the drive current from thecurrent supply section 251. - As described above, the
display unit 200 of this embodiment can vary the drive voltage supplied to thesource driver 270, according to the display mode of thedisplay unit 200. This makes it possible to implement low-power modes for reducing the power consumption of thedisplay unit 200 compared to the normal mode and/or extending the life of thedisplay unit 200. Also, thedisplay unit 200 allows the drive voltage which is supplied to thesource driver 270 to be set to a value according to user preferences. This allows the user to specify a low-power mode of thedisplay unit 200 appropriately by making appropriate trade-offs between easy screen viewing and low power consumption. - The
information processing unit 100 anddisplay unit 200 according to this embodiment allow the display mode of thedisplay unit 200 to be specified according to the frequency of the data transfer clock. Consequently, theinformation processing unit 100 can slow the refresh rate, reduce the power consumption, and extend the life of thedisplay unit 200 even if thedisplay unit 200 is not provided with a low-power mode which corresponds to the frequency of the data transfer clock. Also, thedisplay unit 200 can accept an instruction of specification of a display mode via the same one as an interface provided on a typical display or other display unit. - Furthermore, the
information processing unit 100 and/ordisplay unit 200 according to this embodiment can set thedisplay unit 200 to a low-power mode which restricts the luminance range of pixels in comparison to the normal mode if there is no input from the user of theinformation processing unit 100 for a certain period of time. This makes it possible to set thedisplay unit 200 to a low-power mode while the user of theinformation processing unit 100 is not operating theinformation processing unit 100, and thus to reduce the power consumption and extend the life of thedisplay unit 200. - Furthermore, the
information processing unit 100 and/ordisplay unit 200 according to this embodiment can set thedisplay unit 200 to a low-power mode which restricts the luminance range of pixels in comparison to the normal mode if the frequency at which theimage memory 220 is updated in theinformation processing unit 100 or the like is lower than a preset value. This makes it possible to set thedisplay unit 200 to a low-power mode while the user of theinformation processing unit 100 is not operating theinformation processing unit 100, and thus to reduce the power consumption and extend the life of thedisplay unit 200. - Furthermore, the
information processing unit 100 and/ordisplay unit 200 according to this embodiment can set an available range of the luminance for one part of pixels used to form images displayed on the display unit in a low-power mode, such that it will be different from an available range of the luminance for another part of the pixels used to form the images. This makes it possible to lower the voltage used for driving one part of the pixels in thepanel 230, and thus to reduce the power consumption and extend the life of thedisplay unit 200. - Furthermore, the
display unit 200 according to this embodiment can make the polarity inversion cycle of the potential difference which is applied to the pixels in thepanel 230 in a low-power mode longer than that in the normal mode. This makes it possible to prolong the cycle of voltage fluctuations in the pixels in thepanel 230, and thus to reduce the power consumption and extend the life of thedisplay unit 200. - Furthermore, the
display unit 200 according to the variation of this embodiment can vary the drive current supplied to thesource driver 271, according to the display mode of thedisplay unit 200. This makes it possible to implement low-power modes for reducing the power consumption of thedisplay unit 200 compared to the normal mode and/or extending the life of thedisplay unit 200. Also, thedisplay unit 200 allows the drive current which is supplied to thesource driver 271 to be set to a value according to user preferences. This allows the user to specify a low-power mode of thedisplay unit 200 appropriately by making appropriate trade-offs between easy screen viewing and low power consumption. - In the drawings and specifications there has been set forth a preferred embodiment of the invention and, although specific terms are used, the description thus given uses terminology in a generic and descriptive sense only and not for purposes of limitation. For example, instead of the
display unit 200 according to this embodiment, it is also possible to use a computer or terminal which further comprises all or part of theCPU 110,ROM 115,RAM 120,communications interface 125,hard disk drive 130,floppy disk drive 135, CD-ROM drive 140,input device 145, and theoutput device 150 in theinformation processing unit 100.
Claims (22)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001395280A JP3836721B2 (en) | 2001-12-26 | 2001-12-26 | Display device, information processing device, display method, program, and recording medium |
Publications (2)
Publication Number | Publication Date |
---|---|
US20030122807A1 true US20030122807A1 (en) | 2003-07-03 |
US7057610B2 US7057610B2 (en) | 2006-06-06 |
Family
ID=27601738
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/248,149 Expired - Lifetime US7057610B2 (en) | 2001-12-26 | 2002-12-20 | Display unit, information processing unit, display method, program, and recording medium |
Country Status (2)
Country | Link |
---|---|
US (1) | US7057610B2 (en) |
JP (1) | JP3836721B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070132710A1 (en) * | 2005-12-14 | 2007-06-14 | Sony Corporation | Display |
US20100188392A1 (en) * | 2009-01-23 | 2010-07-29 | Lee Jae-Sung | Organic light emitting display device, method of driving the same and power saving unit thereof |
CN105185291A (en) * | 2015-09-07 | 2015-12-23 | 京东方科技集团股份有限公司 | Display driving method and device and display device |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005148085A (en) * | 2003-11-11 | 2005-06-09 | Semiconductor Energy Lab Co Ltd | Display apparatus, driving method of display apparatus and electronic appliance |
US7532195B2 (en) * | 2004-09-27 | 2009-05-12 | Idc, Llc | Method and system for reducing power consumption in a display |
TWI307872B (en) * | 2005-03-11 | 2009-03-21 | Himax Tech Inc | Power saving method of a chip-on-glass liquid crystal display |
US20080204481A1 (en) * | 2005-04-20 | 2008-08-28 | Freescale Semiconductor, Inc. | Device and Method for Controlling a Backlit Display |
KR101319088B1 (en) * | 2006-11-30 | 2013-10-17 | 엘지디스플레이 주식회사 | Picture Mode Controller for Flat Panel and Flat Panel Display Device Including the same |
JP2010134381A (en) * | 2008-12-08 | 2010-06-17 | Sharp Corp | Display method, display, and computer program |
KR101644804B1 (en) * | 2009-09-09 | 2016-08-03 | 삼성전자주식회사 | Image forming apparatus and low power mode control method thereof |
JP5665791B2 (en) * | 2012-04-12 | 2015-02-04 | トムソン ライセンシングThomson Licensing | Apparatus and method for processing images in a spatial light modulated display system |
JP7398926B2 (en) | 2019-10-23 | 2023-12-15 | 上海天馬微電子有限公司 | liquid crystal display device |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5828367A (en) * | 1993-10-21 | 1998-10-27 | Rohm Co., Ltd. | Display arrangement |
US6005559A (en) * | 1993-12-28 | 1999-12-21 | Canon Kabushiki Kaisha | Display apparatus with a power conserving display |
US6046737A (en) * | 1996-02-14 | 2000-04-04 | Fujitsu Limited | Display device with a display mode identification function and a display mode identification method |
US20010044332A1 (en) * | 2000-05-19 | 2001-11-22 | Fujitsu Limited | Information device, power-saving-mode switching method, and recording medium storing power-saving-mode switching program |
US20010045944A1 (en) * | 2000-03-31 | 2001-11-29 | Ricoh Company, Ltd. | Display device, image forming apparatus, recording medium and display method |
US6339422B1 (en) * | 1997-10-28 | 2002-01-15 | Sharp Kabushiki Kaisha | Display control circuit and display control method |
US20020041281A1 (en) * | 2000-10-06 | 2002-04-11 | Toshihiro Yanagi | Active matrix type display and a driving method thereof |
US6417829B1 (en) * | 1999-06-03 | 2002-07-09 | Samsung Electronics Co., Ltd. | Multisync display device and driver |
US6603469B1 (en) * | 2000-08-28 | 2003-08-05 | Palm, Inc. | Method and apparatus for user selectable display mode for intelligently enhancing battery life |
US20030222866A1 (en) * | 2002-05-30 | 2003-12-04 | Eastman Kodak Company | Display driver and method for driving an emissive video display in an image displaying device |
-
2001
- 2001-12-26 JP JP2001395280A patent/JP3836721B2/en not_active Expired - Fee Related
-
2002
- 2002-12-20 US US10/248,149 patent/US7057610B2/en not_active Expired - Lifetime
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5828367A (en) * | 1993-10-21 | 1998-10-27 | Rohm Co., Ltd. | Display arrangement |
US6005559A (en) * | 1993-12-28 | 1999-12-21 | Canon Kabushiki Kaisha | Display apparatus with a power conserving display |
US6046737A (en) * | 1996-02-14 | 2000-04-04 | Fujitsu Limited | Display device with a display mode identification function and a display mode identification method |
US6339422B1 (en) * | 1997-10-28 | 2002-01-15 | Sharp Kabushiki Kaisha | Display control circuit and display control method |
US6417829B1 (en) * | 1999-06-03 | 2002-07-09 | Samsung Electronics Co., Ltd. | Multisync display device and driver |
US20010045944A1 (en) * | 2000-03-31 | 2001-11-29 | Ricoh Company, Ltd. | Display device, image forming apparatus, recording medium and display method |
US20010044332A1 (en) * | 2000-05-19 | 2001-11-22 | Fujitsu Limited | Information device, power-saving-mode switching method, and recording medium storing power-saving-mode switching program |
US6603469B1 (en) * | 2000-08-28 | 2003-08-05 | Palm, Inc. | Method and apparatus for user selectable display mode for intelligently enhancing battery life |
US20020041281A1 (en) * | 2000-10-06 | 2002-04-11 | Toshihiro Yanagi | Active matrix type display and a driving method thereof |
US20030222866A1 (en) * | 2002-05-30 | 2003-12-04 | Eastman Kodak Company | Display driver and method for driving an emissive video display in an image displaying device |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070132710A1 (en) * | 2005-12-14 | 2007-06-14 | Sony Corporation | Display |
US8300005B2 (en) * | 2005-12-14 | 2012-10-30 | Sony Corporation | Display that implements image displaying and light reception concurrently or alternately |
US20100188392A1 (en) * | 2009-01-23 | 2010-07-29 | Lee Jae-Sung | Organic light emitting display device, method of driving the same and power saving unit thereof |
US8368684B2 (en) * | 2009-01-23 | 2013-02-05 | Samsung Display Co., Ltd. | Organic light emitting display device, method of driving the same and power saving unit thereof |
CN105185291A (en) * | 2015-09-07 | 2015-12-23 | 京东方科技集团股份有限公司 | Display driving method and device and display device |
US10127854B2 (en) | 2015-09-07 | 2018-11-13 | Boe Technology Group Co., Ltd. | Display driving method, apparatus and display device that generates ananalog power supply voltage for a source driver chip according to brightness of sub-pixels |
Also Published As
Publication number | Publication date |
---|---|
JP3836721B2 (en) | 2006-10-25 |
JP2003195828A (en) | 2003-07-09 |
US7057610B2 (en) | 2006-06-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7724269B2 (en) | Device for driving a display apparatus | |
US5828367A (en) | Display arrangement | |
US7133013B2 (en) | Display device driving circuit, driving method of display device, and image display device | |
US7102610B2 (en) | Display system with frame buffer and power saving sequence | |
US7030850B2 (en) | Signal drive circuit, display device, electro-optical device, and signal drive method | |
US8344981B2 (en) | Display driver, display device, and drive method | |
US20060071893A1 (en) | Source driver, electro-optic device, and electronic instrument | |
US20020196241A1 (en) | Scan-driving circuit, display device, electro-optical device, and scan-driving method | |
US7015886B2 (en) | Scanning line driver circuits, electrooptic apparatuses, electronic apparatuses and semiconductor devices | |
US20060050011A1 (en) | Display apparatus and drive control method thereof | |
JPWO2006035843A1 (en) | Timing signal generating circuit, electronic device, display device, image receiving device, and driving method | |
US7057610B2 (en) | Display unit, information processing unit, display method, program, and recording medium | |
JP2003216127A (en) | Driving device for display device and driving method of display device | |
KR100464898B1 (en) | Method for driving active matrix type liquid crystal display | |
JP2003162267A (en) | Display driving circuit, electro-optical device, electronic equipment, and display driving method | |
JP2002244623A (en) | System and circuit for driving liquid crystal display device | |
US20080062102A1 (en) | Liquid crystal display device and control method used in same | |
JP3726910B2 (en) | Display driver and electro-optical device | |
JPH10116056A (en) | Device and method to drive liquid crystal display device | |
JP4830424B2 (en) | Drive device | |
JPH11282422A (en) | Liquid crystal display device | |
KR101001989B1 (en) | Apparatus and method driving liquid crystal display device | |
JP3309839B2 (en) | Liquid crystal display | |
US20040113900A1 (en) | Image display device and method of supplying writing electric potential to an image display device | |
JPH06230340A (en) | Driving circuit of liquid crystal display device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW Y Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KATAOKA, RIEKO;KOBAYASHI, MASAKI;OGAWA, HIDEKI;AND OTHERS;REEL/FRAME:013812/0201;SIGNING DATES FROM 20030129 TO 20030210 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: TWITTER, INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:INTERNATIONAL BUSINESS MACHINES CORPORATION;REEL/FRAME:032075/0404 Effective date: 20131230 |
|
REMI | Maintenance fee reminder mailed | ||
FPAY | Fee payment |
Year of fee payment: 8 |
|
SULP | Surcharge for late payment |
Year of fee payment: 7 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.) |
|
FEPP | Fee payment procedure |
Free format text: 11.5 YR SURCHARGE- LATE PMT W/IN 6 MO, LARGE ENTITY (ORIGINAL EVENT CODE: M1556) |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 12TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1553) Year of fee payment: 12 |
|
AS | Assignment |
Owner name: MORGAN STANLEY SENIOR FUNDING, INC., MARYLAND Free format text: SECURITY INTEREST;ASSIGNOR:TWITTER, INC.;REEL/FRAME:062079/0677 Effective date: 20221027 Owner name: MORGAN STANLEY SENIOR FUNDING, INC., MARYLAND Free format text: SECURITY INTEREST;ASSIGNOR:TWITTER, INC.;REEL/FRAME:061804/0086 Effective date: 20221027 Owner name: MORGAN STANLEY SENIOR FUNDING, INC., MARYLAND Free format text: SECURITY INTEREST;ASSIGNOR:TWITTER, INC.;REEL/FRAME:061804/0001 Effective date: 20221027 |